• if the animal already has some passive immunity from it's mother eg transmitted to a calf in the colostrum (first milk)
• if the animal is not in good health and is unable to mount a good immune response
• if the animal is being treated with a drug (such as corticosteroids) that reduces the immune response 
• if the vaccine has not been stored properly
• in any population of animals some individuals may not respond and do not develop immunity following vaccination

Cattle Vaccines Available in the UK

Below is a list of all Bovine vaccines licensed for use in the UK (Correct as at 1^st October 2013). Not all brands may be available depending upon marketing decisions by the various marketing license holders. Also, the content of individual vaccines may be changed so you are advised to check the current details for these vaccine brands at the Veterinary Medicines Directorate website (www.vmd.defra.gov.uk )

Key

BC – Bovine coronavirus

BPi- Bovine parainfluenzavirus 3

BR – Bovine rotavirus

BRSV – Bovine respiratory syncytial virus

BT – Bluetongue virus

BVDV – Bovine viral diarrhoea virus

CB- Coxiella burnetti

CC – Clostridium chauvoei

CH - Clostridium haemolyticum

CN - Clostridium novyi,

CP - Clostridium perfringens

CSe - Clostridium septicum,

CSo= Clostridium sordellii,

CT- Clostridium tetani

DV - Dictyocaulus viviparus

EC – Escherichia coli

FMDV – Foot and Mouth Disease Virus

IBRV – Infectious bovine rhinotracheitis virus

LB – Leptospira borgpetersenii

LH – Leptospira hardjo

MH – Mannheimia haemolytica

SA – Staphylococcus aureus

SD- Salmonella  dublin

ST – Salmonella typhymurium

SV – Schmallenberg virus

TV- Trichophyton verrucosum

Side Effects
There are a number of side-effects that may be seen following vaccination, including the following :

• The organisms in live vaccines can sometimes cause mild signs of the disease and they can be transferred to other animals in a herd and cause mild signs of disease in them as well
• Live vaccines may damage the fetus in pregnant animals, so they should not be used in pregnant animals if a killed vaccine is available.
• Some live vaccines can result in a long term "latent" infection which may affect blood tests and have implications on the future movement of animals
• Vaccines can cause a local reaction and irritation at the site of injection
• Hair loss, and sometimes a change of hair colour can occur at the injection site
• If the vaccine is administered by injection without cleaning the skin surface infection may be introduced into the site resulting in abscess formation
• Rarely an individual animal may show a severe shock (anaphylactic) reaction following vaccination. In cattle this most often shows as sudden onset breathing difficulty. Prompt veterinary attention is needed or the animals life can be at risk.

Storage
Vaccines will lose their potency if they are not stored properly. They should be stored as specified by the manufacturers, and usually this will require storage in a refrigerator at 2-8^o C. Most vaccines should not be frozen, and they should not be allowed to come into contact with direct sunlight, or disinfectants.

Frequency of Administration
The frequency of administration of vaccines depends on several factors including the following :

• the type of vaccine
• the age of the animal
• the circumstances under which the vaccine is being given, and 
• the route of administration. 

Withdrawal Periods
Cattle can not be sent for slaughter and milk may not be sent for human consumption after the administration of some medications. Vaccines usually have a withdrawal period of nil for slaughter and milk.